Understanding the workflow of the messages in a generic server implementation in Erlang
- by Chiron
The following code is from "Programming Erlang, 2nd Edition". It is an example of how to implement a generic server in Erlang.
-module(server1).
-export([start/2, rpc/2]).
start(Name, Mod) ->
register(Name, spawn(fun() -> loop(Name, Mod, Mod:init()) end)).
rpc(Name, Request) ->
Name ! {self(), Request},
receive
{Name, Response} -> Response
end.
loop(Name, Mod, State) ->
receive
{From, Request} ->
{Response, State1} = Mod:handle(Request, State),
From ! {Name, Response},
loop(Name, Mod, State1)
end.
-module(name_server).
-export([init/0, add/2, find/1, handle/2]).
-import(server1, [rpc/2]).
%% client routines
add(Name, Place) -> rpc(name_server, {add, Name, Place}).
find(Name) -> rpc(name_server, {find, Name}).
%% callback routines
init() -> dict:new().
handle({add, Name, Place}, Dict) -> {ok, dict:store(Name, Place, Dict)};
handle({find, Name}, Dict) -> {dict:find(Name, Dict), Dict}.
server1:start(name_server, name_server).
name_server:add(joe, "at home").
name_server:find(joe).
I tried so hard to understand the workflow of the messages. Would you please help me to understand the workflow of this server implementation during the executing of the functions: server1:start, name_server:add and name_server:find?
